Howard, Virginia J.

Background: In CREST2, intensive medical management of subjects’ vascular risk factors is overseen by the site Principal Investigator (PI) and implemented by a designated Medical Management Physician (MMP) and coordinator. These physicians have different specialties and experience with risk factor management. We sought to determine the relationship between risk factor control and PI and MMP specialty. Methods: Data on 613 patients with at least 1 follow-up visit from 105 CREST2 sites were used for these analyses. CREST2 sites were categorized based on both PI specialty and MMP specialty. Specialty of the site-designated primary MMP was used for sites with more than one MMP. We compared the percentage of patients in target at last follow-up visit for the primary risk factors, LDL < 70 mg/dL and SBP <140 mm Hg, among PI specialties and MMP specialties, using the chi-square test. Results: The table shows the number of patients by PI and MMP specialty, as well as their control of SBP and LDL. There were no significant differences in control of SBP or LDL by PI specialty. There was a trend toward an association between LDL control and MMP specialty, with higher rates of LDL control at sites with Internal Medicine MMP specialists and lower rates of control with Vascular Surgery MMPs. SBP control rates were not significantly different across MMP specialties. Conclusions: In this early analysis of risk factor control in the CREST2 study, site PI and MMP specialty did not have a significant effect on LDL and SBP during follow-up. This suggests that protocol care pathways are generalizable to diverse physicians.

Rationale: Asymptomatic carotid stenosis is commonly seen in medical practice. CREST-2 is a pair of concurrent two-arm multi-site randomized trials of intensive medical management versus intensive medical management in combination with revascularization by endarterectomy or stenting. It is not known how often patients entering the trials have opportunities for further risk factor reduction at study entry and whether these opportunities vary across trial centers. Methods: Baseline data on 683 patients from 109 clinical sites were used for these analyses. We determined the rates of control at baseline for systolic blood pressure (SBP), defined as <140 mmHg (or ≥140 with >15mmHg orthostatic drop), and low density lipoprotein (LDL), defined as <70 mg/dl. We then tested differences in these baseline control rates by site-related characteristics, including site type, StrokeNet site vs. not, specialty of site Principal Investigator (PI), type of hospital, central vs local IRB, type of research team and whether site is enrolling in one or both trials. P-value <0.05 was considered significant. Results: At baseline, the mean SBP was 140.4±20.5 mmHg, but only 62% of participants were in target. The mean LDL at baseline was 83.7±36.9, mg/dl, with 42% in target. None of the site characteristics were associated with a higher level of control for SBP at baseline. The only characteristic associated with having a higher level of LDL control was sites enrolling in only the CAS trial (57%) compared to those enrolling in the CEA only (24%) or in both trials (42%) (p=0.02). Conclusions: Opportunities to improve on risk factors are common among CREST-2 participants, but site characteristics did not predict the likelihood of being at goal for SBP while sites enrolling in only the CAS trial had a higher level of LDL control.

Background and Purpose— Multicenter clinical trials attempt to select sites that can move rapidly to randomization and enroll sufficient numbers of patients. However, there are few assessments of the success of site selection. Methods— In the CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trials), we assess factors associated with the time between site selection and authorization to randomize, the time between authorization to randomize and the first randomization, and the average number of randomizations per site per month. Potential factors included characteristics of the site, specialty of the principal investigator, and site type. Results— For 147 sites, the median time between site selection to authorization to randomize was 9.9 months (interquartile range, 7.7, 12.4), and factors associated with early site activation were not identified. The median time between authorization to randomize and a randomization was 4.6 months (interquartile range, 2.6, 10.5). Sites with authorization to randomize in only the carotid endarterectomy study were slower to randomize, and other factors examined were not significantly associated with time-to-randomization. The recruitment rate was 0.26 (95% confidence interval, 0.23–0.28) patients per site per month. By univariate analysis, factors associated with faster recruitment were authorization to randomize in both trials, principal investigator specialties of interventional radiology and cardiology, pre-trial reported performance >50 carotid angioplasty and stenting procedures per year, status in the top half of recruitment in the CREST trial, and classification as a private health facility. Participation in StrokeNet was associated with slower recruitment as compared with the non-StrokeNet sites. Conclusions— Overall, selection of sites with high enrollment rates will likely require customization to align the sites selected to the factor under study in the trial. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT02089217.

Rationale Trials conducted decades ago demonstrated that carotid endarterectomy by skilled surgeons reduced stroke risk in asymptomatic patients. Developments in carotid stenting and improvements in medical prevention of stroke caused by atherothrombotic disease challenge understanding of the benefits of revascularization. Aim Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial (CREST-2) will test whether carotid endarterectomy or carotid stenting plus contemporary intensive medical therapy is superior to intensive medical therapy alone in the primary prevention of stroke in patients with high-grade asymptomatic carotid stenosis. Methods and design CREST-2 is two multicenter randomized trials of revascularization plus intensive medical therapy versus intensive medical therapy alone. One trial randomizes patients to carotid endarterectomy plus intensive medical therapy versus intensive medical therapy alone; the other, to carotid stenting plus intensive medical therapy versus intensive medical therapy alone. The risk factor targets of centrally directed intensive medical therapy are LDL cholesterol <70 mg/dl and systolic blood pressure <140 mmHg. Study outcomes The primary outcome is the composite of stroke and death within 44 days following randomization and stroke ipsilateral to the target vessel thereafter, up to four years. Change in cognition and differences in major and minor stroke are secondary outcomes. Sample size Enrollment of 1240 patients in each trial provides 85% power to detect a treatment difference if the event rate in the intensive medical therapy alone arm is 4.8% higher or 2.8% lower than an anticipated 3.6% rate in the revascularization arm. Discussion Management of asymptomatic carotid stenosis requires contemporary randomized trials to address whether carotid endarterectomy or carotid stenting plus intensive medical therapy is superior in preventing stroke beyond intensive medical therapy alone. Whether carotid endarterectomy or carotid stenting has favorable effects on cognition will also be tested. Trial registration United States National Institutes of Health Clinicaltrials.gov NCT02089217

Background The association between resting heart rate and ischemic stroke remains unclear. Aim To examine the association between resting heart rate and ischemic stroke. Methods A total of 24 730 participants (mean age: 64 ± 9·3 years; 59% women; 41% blacks) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study who were free of stroke at the time of enrollment (2003–2007) were included in this analysis. Resting heart rate was determined from baseline electrocardiogram data. Heart rate was examined as a continuous variable per 10 bpm increase and also as a categorical variable using tertiles (<61 bpm, 61 to 70 bpm, and >70 bpm). First-time ischemic stroke events were identified during follow-up and adjudicated by physician review. Results Over a median follow-up of 7·6 years, a total of 646 ischemic strokes occurred. In a Cox regression model adjusted for socio-demographics, cardiovascular risk factors, and potential confounders, each 10 bpm increase in heart rate was associated with a 10% increase in the risk of ischemic stroke (hazard ratio = 1·10, 95% confidence interval = 1·02, 1·18). In the categorical model, an increased risk of ischemic stroke was observed for heart rates in the middle (hazard ratio = 1·29, 95% confidence interval = 1·06, 1·57) and upper (hazard ratio = 1·37, 95% confidence interval = 1·12, 1·67) tertiles compared with the lower tertile. The results were consistent when the analysis was stratified by age, gender, race, exercise habits, hypertension, and coronary heart disease. Conclusion In REGARDS, high resting heart rates were associated with an increased risk of ischemic stroke compared with low heart rates. Further research is needed to examine whether interventions aimed to reduce heart rate decrease stroke risk.

Background: With patients living a decade or longer post-procedure, long-term data are needed to assess the durability of carotid artery stenting versus carotid endarterectomy. Identifying characteristics of those consenting or declining to continue in long-term follow-up may suggest strategies to improve retention in clinical trials. Purpose: This report describes differences between patients choosing or declining to continue follow-up for up to 10 years in the Carotid Revascularization Endarterectomy versus Stenting Trial. Methods: Following completion of the primary outcome, patients who were in active Carotid Revascularization Endarterectomy versus Stenting Trial follow-up were asked to continue beyond their original 4-year commitment for a maximum of 10 years. The characteristics of those who consented were compared with those who declined. Univariate and multivariable logistic regression were used for analysis, and backwards stepwise logistic regression (the most parsimonious model) was used to determine the factors associated with continuation. Results: Of the 1921 active Carotid Revascularization Endarterectomy versus Stenting Trial participants for whom consent to extend follow-up was requested, 1695 (88%; mean age: 68.4) consented; 226 (12%; mean age: 69.6) declined. Of those who did not consent versus those who consented, 66% versus 48% were symptomatic at baseline (p < 0.0001), at follow-up 28% versus 20% were smokers (p = 0.009), 85% versus 90% were hypertensive (p = 0.01), and 84% versus 94% were dyslipidemic (p < 0.0001). Additional factors that differed between those who did not consent and those who consented included the mean number of years in the study at time of consent (4.8 years vs 3.7 years (p = <0.0001)) and patients from sites that enrolled <30 patients compared to sites randomizing 30 or more (70% vs 52% (p < 0.0001)). Multivariable logistic regression indicated that those with lesser odds of consenting to the extended follow-up were older (odds ratio: 0.80; 95% confidence interval: 0.67, 0.96), more likely to be symptomatic (odds ratio: 0.58; 95% confidence interval: 0.42, 0.80), smokers (odds ratio: 0.48; 95% confidence interval: 0.34, 0.70), were in the study 5+ years versus <3 (odds ratio: 0.21; 95% confidence interval: 0.13, 0.34), and at a site that randomized <30 patients (odds ratio: 0.46; 95% confidence interval: 0.33, 0.63), while patients with dyslipidemia at follow-up had increased odds of consenting (odds ratio: 2.28 (1.47, 3.54)). Conclusion: Symptomatic status, increasing age, randomized at lower volume centers, and longer time in follow-up were associated with reduced odds of consenting to long-term follow-up. Identifying factors associated with reduced willingness to extend participation long-term can suggest targeted strategies to improve retention in future clinical trials.

Background The Carotid Revascularization Endarterectomy Versus Stenting Trial ( CREST ) is a multicenter randomized trial of stenting versus endarterectomy in patients with symptomatic and asymptomatic carotid disease. This study assesses management of vascular risk factors. Methods and Results Management was provided by the patient's physician, with biannual monitoring results collected by the local site. Therapeutic targets were low‐density lipoprotein, cholesterol <100 mg/dL, systolic blood pressure <140 mm Hg, fasting blood glucose <126 mg/dL, and nonsmoking status. Optimal control was defined as achieving all 4 goals concurrently. Generalized estimating equations were used to compare risk factors at baseline with those observed in scheduled follow‐up visits for up to 48 months. In the analysis cohort of 2210, significant improvements in risk‐factor control were observed across risk factors for all follow‐up visits compared with baseline. At 48 months, achievement of the low‐density lipoprotein cholesterol goal improved from 59.1% to 73.6% ( P <0.001), achievement of the systolic blood pressure goal improved from 51.6% to 65.1% ( P <0.001), achievement of the glucose goal improved from 74.9% to 80.7% ( P =0.0101), and nonsmoking improved from 74.4% to 80.9% ( P <0.0001). The percentage with optimal risk‐factor control also improved significantly, from 16.7% to 36.2% ( P <0.001), but nearly 2 of 3 study participants did not achieve optimal control during the study. Conclusions Site‐based risk‐factor control improved significantly in the first 6 months and over the long term in CREST but was often suboptimal. Intensive medical management should be considered for future trials of carotid revascularization. Clinical Trial Registration URL: ClinicalTrials.gov. Unique identifier: NCT00004732.